Nitrogen concentration in shoot tissues during growth of pickling cucumber plants

In order to determine the shoot nitrogen concentration during growth of a pickling cucumber crop, plants were grown with three nutrient levels. At the whole plant level and also in vegetative tissues, N% decreases with growth and data fitted well the model proposed in the literature to explain this phenomenon, for each of the nutrient treatments. No decline of N concentration was found in fruits, and an average value of 3.85% was determined.Évolution de la concentration d'azote dans les parties aériennes des plantes de cornichon au cours de leur croissance. Afin de déterminer l'évolution de la concentration d'azote dans les parties aériennes des plantes de cornichon au cours de leur croissance, trois lots de plantes ont été cultivés avec des doses différentes de solution nutritive. Il apparaît que la concentration d'azote diminue avec la croissance dans l'ensemble de la plante, de même que dans les tissus végétatifs. Pour chacune des doses de solution nutritive, les données expérimentales suivent le modèle proposé dans la littérature. Il n'a été observé aucune diminution de la concentration d'azote dans les fruits et la valeur moyenne de 3,85 % a été déterminée

Acúmulo e repartição da matéria seca da planta de pepino tipo conserva sob três doses de nutrientes minerais Dry matter accumulation and distribution of pickling cucumber plants under three mineral nutrient levels

Determinou-se o efeito de três doses de nutrientes minerais sobre o acúmulo e distribuição da matéria seca da planta de pepino tipo conserva, híbrido Crispina. As plantas foram cultivadas em sacolas plásticas com 4,6kg de substrato composto por uma mistura de 40% de casca de arroz e 60% de solo, no interior de uma estufa de polietileno, na primavera de 1998 e no verão de 1999. Foi empregado um delineamento experimental de blocos casualizados, com três repetições e 15 plantas por parcela. Os tratamentos foram constituídos por três níveis múltiplos de uma dose padrão de nutrientes aplicada para cada planta, contendo N-P-K-Ca e Mg nas quantidades de 0,8-0,12-0,8-0,46-0,086g.pl-1, com 0,33m<IMG SRC="http:/img/revistas/cr/v31n3/a04img01.gif"> de solução de micronutrientes e 0,07m<IMG SRC="http:/img/revistas/cr/v31n3/a04img01.gif"> de quelato de ferro. Os níveis corresponderam às quantidades de 50%, 100% e 150% da dose padrão, denominados de tratamentos T1, T2 e T3, respectivamente, aplicados semanalmente através da fertirrigação em todas as plantas de uma mesma parcela. Determinou-se a matéria seca dos diferentes órgãos da parte aérea da planta a intervalos semanais. Houve efeito significativo dos tratamentos no acúmulo da matéria seca, nos dois experimentos. A maior fração foi alocada para os frutos, atingindo o valor mais elevado de 0,64 na primavera. Concluiu-se que a distribuição da matéria seca desse material vegetal não é constante, sofrendo interações com as variáveis do ambiente.<br>It was determined the effect of three mineral nutrient levels on dry matter accumulation and distribution of pickling cucumber plants, hybrid Crispina, grown inside a polyethylene greenhouse, in spring 1998 and in summer 1999. Planting was made in bags filled with 4.6kg of a substrate mixture composed by 40% rice husks and 60% soil. A randomized block experimental design was used, with three replications and15 plants per plot. A reference nutrient dose was supplied weekly to each one of the plants, with the following composition, in g.plant-1 : 0.8 N, 0.12 P, 0.8 K, 0.46 Ca, 0.086 Mg, 0.33m<IMG SRC="http:/img/revistas/cr/v31n3/a04img01.gif"> of a micronutrients mixture and 0.07m<IMG SRC="http:/img/revistas/cr/v31n3/a04img01.gif"> of an iron chelate. Treatments consisted of three levels of the reference nutrient dose, in the proportion of 50%, 100% and 150%, named treatments T1, T2 and T3, respectivelly, applied to plants weekly by fertigation. Dry matter of aerial organs was measured weekly. It was observed a significant effect of nutrition levels on dry matter accumulation, in both experiments. The higher fraction allocated to fruits was 0.64, in the first experiment. It was concluded that dry matter distribution on this material is not constant, due to interactions with environmental variables